Dimmable fluorescent lamp package

ABSTRACT

A lamp package includes a base for insertion into an electrical socket, a complete dimmable ballast circuit contained within and electrically connected to the base, and a fluorescent lamp, including a CFLP, connected to and dimmed through the ballast circuit. The base includes a thermally conductive body, such as an epoxy, so that the base dissipates heat from the ballast. The package also includes a diffuser, possibly connected directly to the base, that surrounds the lamp. In a further aspect of the invention, the lamp package includes one or more of a variety of sensors, such as a photodetector, that are connected to the dimmable ballast circuit, thereby providing a self-dimming lamp. The self-dimming lamp is suitable for use in a standard Edison socket and with CFLPs to provide a self-regulated light output. Various lighting schemes may be incorporated into the dimmable ballast circuit, such as regulated light output applications.

RELATED APPLICATION

This application is a division of U.S. patent application Ser. No.11/139,161, filed May 27, 2005 entitled Dimmable Fluorescent Lamp Packwhich is a continuation-in-part of and claims priority to U.S. patentapplication Ser. No. 10/678,004, filed on Oct. 2, 2003, entitled COMPACTFLUORESCENT LAMP PACKAGE, by Thomas J. Ribarich, which is based on andclaims priority to U.S. Provisional Application No. 60/416,350, filed onOct. 4, 2002, entitled COMPACT FLUORESCENT LAMP MULTI-CHIP MODULESCREWBASE BALLAST, the contents of which are herein incorporated byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a self contained lamp controland lamp package, and relates more specifically to a self contained lampfor automatic light level adjustment.

2. Description of Related Art

Referring to FIG. 1, a conventional incandescent light bulb 5 includesbase 10, and evacuated envelope or diffuser 14. Diffuser 14, which istypically pear-shaped, surrounds a filament (not shown) that iselectrically connected to base 10 for electrical connection to aconventional lamp socket. A well-known base is an Edison screw-base, asshown, which is electrically connectable to an Edison screw socket.

In recent years, compact fluorescent lamp packages have been introducedinto the market. These lamp packages are particularly desirable becauseof their energy efficiency.

Referring to FIG. 2A, an example prior art compact fluorescent lamppackage (CFLP) 7 is shown consisting of fluorescent lamp 12, lamp holder13, and auxiliary housing 15 for interfacing between lamp holder 13 andbase 10. Typically, housing 15 also houses a complete ballast 17.However, it should be noted that ballast 17 has also been placed intobase 10, while either retaining housing 15 or removing this housing. Inmost CFLPs an Edison screw-base is used as base 10 for a reliablemechanical and electrical connection to a standard Edison socket,although other sockets are known and used.

The typical height of a standard incandescent light bulb 5 is about 4.5in. However, most conventional CFLPs are typically taller than aconventional incandescent light bulb due to auxiliary elements such asauxiliary housing 15. As a result, a conventional CFLP may extend out ofa lampshade or fixture adapted for an incandescent light bulb, causingan undesirable appearance, or the CFLP may not fit within an existingfixture. This extended height, together with the unusual appearance ofconventional CFLPs, are believed to adversely affect the acceptance ofCFLPs in the marketplace

Another issue with the conventional CFLP is that when ballast 17 ishoused in auxiliary housing 15, the heat generated by ballast 17 cannotescape very efficiently. Referring, for example, to FIG. 2B, in atypical enclosure or downlight fixture 19, the heat generated from thelamp and ballast of a conventional CFLP 7 collects up in the fixturearound the CFLP 7 without any path to escape.

As a result, there is a higher ambient temperature around CFLP 7 whichcauses the internal components of the CFLP 7, especially ballast 17, torun at even higher temperatures, e.g., above 150° C. The increase in theinternal heat decreases reliability, causes field failures and limitsthe use of a conventional CFLP to open rather than enclosed fixtures,all of which further adversely affects the desirability of CFLPs.Nonetheless, it should be noted that when ballast 17 has been placedinto base 10 as described above, the base has acted as a heat sink forthe ballast, helping to dissipate some of this heat.

A further issue with the conventional CFLP is that because of its sizeand operational constraints, such as its high ambient temperature andits use of the conventional Edison socket, it is difficult to realizesome desirable features, such as, for example, a dimming feature wherethe light output of the fluorescent lamp is selected based on a controlsignal or setting. More specifically, conventional incandescent lightstypically use a dimmer control mounted on a wall near an on/off switchfor adjusting the light level. These types of dimming controls operateon various principles but all in essence change the characteristic ofthe electrical power supplied to the light fixture to create variouspower levels supplied to the lamp, thereby affecting the output lightinglevel. However, these types of dimming controls are unsuitable for CFLPsbecause the change in power may extinguish the lamp. As a result, inorder to incorporate a dimming feature into the CFLP, a dimmable ballastcircuit is typically used where the electronic ballast now includes anadditional dimming function that controls the ballast to dim the lamp.However, a mechanism is now needed to control this additional dimmingfunction, thereby making it a difficult challenge to provide a dimmingfeature to a CFLP.

For example, one mechanism that has been used to control a dimmableballast circuit is to dedicate a wire from a wall-mounted dimmer to thefixture. However, if the CFLP is inserted into an Edison socket, thisrequires additional wiring. Specifically, Edison screw sockets typicallyonly provide switched utility power on two wires, a line input and aneutral wire. Accordingly, a third wire is now needed to control thedimming function. However, providing a third wire or connection to theEdison screw socket is a highly undesirable additional requirement torealize a dimming feature.

Another example mechanism that has been used to control a dimmableballast circuit is to send control signals from a switch to the fixturedirectly over the power lines, thereby negating the need for anadditional wire. However, this approach is complex, expensive, and spaceconsuming given that the fixture must now include an interface toreceive and decode the signal. Nonetheless, it should be noted that somesystems that have used this mechanism have also incorporatedadvantageous features, including the use of an external control modulethat allows for the remote and automatic control of the lights. Forexample, a control system may be provided that can control a number ofdifferent areas of lighting to automatically change lighting settingsdepending upon various circumstances, such as evening hours, weekendhours, lengthened days and so forth. However, it should also be notedthat these types of lighting systems typically have limited localintelligence (e.g., the fixtures lack sensor feedback that permitslocalized control) and often control blocks of lights together, ratherthan individual lights.

Another mechanism that has been used to control a dimmable ballastcircuit is to include a manual control directly on the casing of theelectronic ballast of the CFLP so that dimming can be effected. However,CFLPs designed to replace incandescent bulbs often do not permit easyaccess to the CFLP or electronic ballast by the user. In addition, oncethe light level has been set, it is often difficult or inconvenient toreadjust.

A further mechanism that prior fluorescent light systems in general haveused to control dimming is to incorporate a self-dimming function thatautomatically dims the light in reaction to external events. Suchself-dimming functions have included the integration of a heat sensor ora photosensitive control element, such as a photocell, with the dimmingfunction. For example, these systems have interconnected a photocellwith the dimming function to automatically control the turning on/off ofthe light and to maintain a constant light level in a room, all based onthe changing ambient light levels in the room.

In the case of the CFLP in particular, the photocell has been mounteddirectly on the housing 15. This arrangement creates several advantagesas compared to the other dimming mechanisms described above.Specifically, this arrangement allows for individual control of eachCFLP and because of the automatic feedback orientation, each CFLP isself-dimming thereby making the CFLP easier and more convenient to usebecause the user is not required to constantly readjust the light levelas conditions change. In addition, when the CFLP is inserted into anEdison socket, the socket does not require additional wiring. Thismechanism is also less complex and less expensive than prior mechanisms.

Nonetheless, prior CFLPs that have integrated a sensor, like aphotocell, with the dimming function of a dimmable ballast circuitcontinue to have the same issues as described above with reference tothe example CFLP 7. Specifically, these prior CFLPs continue to use ahousing 15 to house the dimmable ballast circuit, thereby creating thesame height and heat issues described above.

SUMMARY OF THE INVENTION

In accordance with an embodiment of the present invention, a fluorescentlamp package and in particular, a CFLP, includes a base, such as anEdison screw-base, for insertion into an electrical socket. A dimmableballast circuit, which can be implemented as a single multi-chip module(MCM), is physically disposed substantially or entirely in the base ofthe lamp, thereby eliminating the need for an auxiliary housing for thedimmable ballast circuit. A fluorescent lamp is connected to the ballastcircuit, which in turn controls the dimming of the lamp. A diffuser mayalso surround the lamp.

Once in the base, the ballast may be potted with a thermal epoxy, forexample, to provide mechanical stability, to act as a thermal transfer,and to act as a sealant against environmental impact, such as moistureor temperatures, thereby allowing the CFLP to be used in outdoorapplications. With respect to heat transfer, the lamp base serves as aheat sink with the threads of the screw-base acting as fins for allowingthe heat generated by the electronic dimmable ballast to escapeefficiently.

According to one aspect of the invention, the fluorescent lamp and thediffuser are mounted directly on the base, although they do not need tobe. The diffuser cover can also be shaped or have an envelopeapproximating that of a conventional incandescent bulb. As such, whenthe base is a standard screw-base, a dimmable CFLP can have theappearance of a conventional incandescent light bulb thereby permittingthe dimmable CFLP to serve as a replacement lamp for a standard dimmableincandescent bulb.

When implemented as a MCM, the dimmable ballast circuit of the presentinvention includes, for example, a control IC, power MOSFETs, bridgerectifier diodes, resistors, capacitors, and inductors all arranged, forexample, on a two-sided circuit board that fits directly inside the lampbase. According to one aspect of the invention, the MCM can bemanufactured in two stages, for example, with design independentcomponents first being installed to create a general purpose type ofmodule, and design dependent modules than being added to create acustomized or application specific dimmable ballast.

Overall, a dimmable CFLP according to this embodiment of the inventionhas a decreased cost and size/height with a reduced component count forthe ballast. The small size of the electronic ballast for the CFLPpermits the overall CFLP to take on the appearance of a conventionalincandescent light bulb. The heat sink capacity of the base of the CFLPpermits the maximum power output of the ballast and lamp to be increaseddue to the attendant heat transfer efficiencies realized. Because theelectronic ballast may be formed with standard and reliablemanufacturing techniques, such as pick and place surface mount, the costof the CFLP is reduced while reliability is improved.

In accordance with a further embodiment of the invention, the dimmableCFLP also includes one or more sensors that provide an indication ofenvironmental conditions. The sensors are operatively coupled to adimming function of the dimmable ballast circuit and provide the ballastcircuit with signals for automatically driving the fluorescent lamp. Inthis way, a CFLP is provided with individualized feedback control andsensing to provide a self-dimming operation.

For example, the sensor may be a photodetector that is positioned on thelamp at a location where ambient light can be sensed in a room toprovide a light-sense-feedback to the electronic dimmable ballast. Thephotodetector may be placed on the lamp base, a socket connector, thefluorescent lamp itself, or the diffuser to detect ambient light. Thephotodetector may be adjustable to have tolerances related to ambientlight that is directly or indirectly influenced by the light of the lampitself. Alternately, or additionally, the electronic dimmable ballastcan provide functionality to compensate a photodetector feedback signalor adjust a control in the electronic ballast output to determine ascale of sensing, lamp control, or both. The electronic dimmable ballastcan also compensate for the measurement of ambient light that isdirectly or indirectly impacted by the light emitted from the lamp underthe control of the electronic ballast.

The photodetector can be very small in dimension so that it is notnoticeable to the ordinary observer, and does not impact a balance oflight output, as might be the case if the light output were shaded bythe photodetector.

Various types of control techniques or goals may be implementedaccording to the invention, including maintaining a constant ambientlight, maintaining hysteresis in a light level output to conserve energyor to compensate for natural light variations that may occur over thecourse of a given day. For example, a room lighted partially withnatural light may have very different light characteristics based onsunny or cloudy days, or whether window shades or blinds are open,partially open, or closed. A room that is partially lit through naturallight can experience wide variations in light levels over the course ofsingle day, for example, from a cloudy morning to a sunny afternoon ordepending upon orientation with respect to the path of travel of thesun. The lighting control according to the present invention cancompensate for all these variations in light levels based either on asensory feedback technique, or a programmed response to particular lightlevels, for example. As an example of a programmed response, the lampcan be programmed to respond to ambient light levels from dawn to dusk,that is, variable periods of time during which one or more programmedresponses may be applied.

The sensor need not be limited to sensing light alone, but can alsosense other events including room occupancy or provide motion detectionfor lighting or security applications.

Other features and advantages of the present invention will becomeapparent from the following description of the invention, which refersto the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a conventional incandescent light bulb.

FIG. 2A shows an example conventional compact fluorescent lamp package.

FIG. 2B shows an example conventional compact fluorescent lamp packageas installed in a recessed downlight fixture.

FIG. 3 shows a schematic of an example dimmable compact fluorescent lamppackage according an embodiment of the present invention.

FIG. 4 schematically shows the physical appearance of an examplemulti-chip module implementing a dimmable ballast circuit used in adimmable compact fluorescent lamp package according to an embodiment ofthe present invention.

FIG. 5 shows the multi-chip module of FIG. 4 as installed in aconventional base of a conventional incandescent light bulb but employedin a dimmable compact fluorescent lamp package according to the presentinvention.

FIG. 6 shows an example dimmable ballast circuit diagram incorporated ina multi-chip module that is used in an embodiment of the presentinvention.

FIG. 7 is an illustration of an example self-dimming compact fluorescentlamp in accordance with an embodiment of the present invention.

FIG. 8 is a block diagram illustrating an example control according tothe present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 3, there is shown an example dimmable CFLP 9 accordingto an embodiment of the present invention, the dimmable CFLP including abase 10, fluorescent lamp 12, and preferably diffuser 14, although thediffuser is not required. Base 10 is adapted such that it may bereceived in a conventional electrical socket suited for receiving anordinary incandescent light bulb. Preferably, CFLP 9 utilizes a screwtype base, such as an Edison screw-base, although other types of basescan be used. Similar to an incandescent light bulb, base 10 in CFLP 9 isused as an electrical connector to the power line.

Preferably, fluorescent lamp 12 can be of any shape or size such as, forexample, U-shaped, double U-shaped, or spiral-shaped. According to oneaspect of the present invention, any kind of fluorescent lamp 12 may beused with changing only a few electronic ballast components selectedaccording to the design requirements of the lamp as discussed later.

Diffuser 14 may be of any shape, size, or color, and is made from anoptically transmissive material such as glass or plastic. According toone aspect of the present invention, both the diffuser and fluorescentlamp 12 are directly connected to base 10, although they does not needto be. In accordance with a further aspect of the invention, diffuser 14is shaped like a pear, which is a shape common to most incandescentlight bulbs. As such, dimmable CFLP 9 according to the present inventioncan have a size and shape resembling a conventional incandescent lightbulb and can be used in all applications suitable for a conventionalincandescent light bulb.

According to a first embodiment of the present invention, a completedimmable electronic ballast circuit for operating fluorescent lamp 12 iscontained substantially or entirely within base 10, thereby eliminatinga need for an auxiliary compartment or similar element used in prior artdevices. According to a second embodiment of the invention, CFLP 9 mayinclude a sensor 11 situated on diffuser 14, for example, and that iscoupled to the dimmable electronic ballast circuit to contribute to anautomatic control function.

As is well known, base 10 includes an open end leading to an interioropen space. According to an aspect of the present invention, thecomplete dimmable ballast circuit for operating fluorescent lamp 12 canbe implemented as a multi-chip module (MCM). According to the firstembodiment of the present invention, the MCM is disposed substantiallyor entirely in the interior space of base 10, as shown by example MCM 16of FIGS. 4 and 5.

In this example of FIG. 4, a portion of MCM 16 is located on one side ofa circuit board 18 and potted with plastic molding 51. Here, components20 are molded within plastic molding 51 to provide good protection forcomponents 20 and good thermal transfer to draw heat away fromcomponents 20. Circuit board 18 includes connections to permitelectronic devices 22 to be mounted to another side of circuit board 18and to be in electrical contact with components 20. The electronicdevices can include passive components such as a filter inductor 24, abus capacitor 26, a resonant inductor 28, and a fuse 30. Terminals 32are also connected to circuit board 18, and provide an electrical pathto the filaments of fluorescent lamp 12. Electronic devices 22 caninclude other items that are active rather than passive, and can betailored to a particular application.

In accordance with the second embodiment of the present invention, aconditioning circuit 63 (FIG. 6) can also be provided on circuit board18 with electrical devices 22 to accept a feedback signal from a sensor11 to contribute to controlling the dimmable electronic ballast circuitof CFLP 9 to obtain a desired output. Connections may be provided asinputs to components 20 on circuit board 18 so that fluorescent lamp 12may be driven in accordance with a particular control technique basedpartially on the feedback signal.

Referring now to FIG. 5, base 10 more specifically includes an open end34, a closed end 36, and a wall 38 surrounding closed end 36. Wall 38surrounds a space that substantially or entirely contains the dimmableelectronic ballast circuit, such as implemented through MCM 16 as shownin FIG. 5. According to an aspect of the invention, the space enclosedby wall 38 can be filled with thermal epoxy 40, for example, to providemechanical stability for the ballast within base 10, to act as a thermaltransfer, and to act as a sealant against environmental impact, such asmoisture or temperatures, thereby allowing the CFLP to be used inoutdoor applications. With respect to thermal transfer, epoxy 40 allowsheat generated by the electronic devices included with MCM 16, forexample, to be transferred more efficiently to wall 38 so that the heatmay be dissipated. Thus, base 10 may function as a heatsink for thedimmable ballast circuit. It should be noted that depending on the finaltemperatures of the components of the ballast and other factors, such asthe requirements of the final application and the lifetime of thecomponents, the use of thermal epoxy 40 may be avoided.

Also, wall 38 functions as an electrical connector for connecting theelectronic ballast circuit to one pole of the power line. Specifically,in the preferred embodiment of the present invention, the electronicballast circuit is connected to the neutral pole via first electricalwire 42. Furthermore, the electronic ballast circuit is electricallyconnectable to the live pole via a second wire 44, which is electricallyconnected to connector 46. Connector 46 is electrically insulated fromwall 38 by insulation ring 48. Together, insulation ring 48 andconnector 46 form closed end 36 of base 10.

Also, as shown by FIG. 5, terminals 32 extend out of thermal epoxy 40and are electrically connected to respective filaments 50 of fluorescentlamp 12. When the CFLP also includes a feedback device, such as sensor11, control line or lines 52 will also extend out of epoxy 40 forconnection to the device to provide a closed loop control in conjunctionwith the dimmable ballast circuit.

Referring now to FIG. 6, there is shown a circuit diagram of an exampledimmable electronic ballast in accordance with the present invention,the electronic ballast being illustrated generally as ballast 60. Asanother example, the dimmable electronic ballast in accordance with thepresent invention can also be implemented using the integrated circuitdescribed in co-pending U.S. patent application Ser. No. 11/063,404(Attorney Docket No. IR-2476 (2-4382)), filed Feb. 22, 2005, entitled“BALLAST DIMMING CONTROL IC” by Thomas J. Ribarich, the contents ofwhich are hereby incorporated by reference. Ballast 60 is more fullydescribed below as one example of the dimmable electronic ballastcircuit of the present invention.

Ballast 60 can be implemented as example MCM 16 with various componentson either side of circuit board 18. In accordance with one aspect of thepresent invention, a number of components of ballast 60 may be userselectable, while others may be supplied as standard operating elements20 as indicated by the dashed line in FIG. 6. While FIG. 6 illustratesone potential configuration for user selectable/standard configurationcomponents, it should be apparent that any number of components may besupplied as a standard configuration, depending on the application, orthat a variety of components may be provided as user selectable that arenot necessarily indicated as such in FIG. 6. For example, resistor RFMINcan be incorporated into the standard configuration, even though it isillustrated as being user selectable in FIG. 6.

Ballast 60 is controlled through a control IC 61 that provides signalsto switch switches MHS and MLS in a half-bridge configuration to supplyappropriately switched power to lamp 12. IC 61 may be, for example, anintegrated circuit sold by the assignee of the present invention underthe designation IR2159. Components and values supplied to control IC 61provide the operating parametrics for control IC 61, including anoscillator frequency limit through capacitor CVCO, a pre-heat frequencythrough capacitors CPH, and a pre-heat current through resistor RIPH.Control IC 61 also provides a dimming function with a range of dimmingdefined by resistors RMIN and RMAX. The dimming control provided to theDIM input on pin 4 of control IC 61 determines a lighting level for lamp12. Input DIM typically ranges from 0.5 to 5.0 Volts, which range istranslated to a lighting range based on the values of resistors RMIN andRMAX.

In accordance with the second embodiment of the present invention asindicated above, a sensor 11 can be used to develop a signal supplied toinput DIM of control IC 61. According to this embodiment, a conditioningcircuit 63 may optionally be used to condition the signal supplied bysensor 11 to obtain a signal suitable for use with input DIM.Alternately, the circuitry represented by conditioning circuit 63 may beincorporated into control IC 61. However, conditioning circuit 63 mayalso be supplied by a user for a specific application, or be providedfor tolerance adjustments or operating range adjustments for sensor 11.That is, conditioning circuit 63 may be incorporated as part of sensor11, so that sensor 11 outputs a signal appropriate for use with controlIC 61. In addition, conditioning circuit 63 may be used to providevarious functionality for sensor 11, including such features ashysteresis, analog to digital conversion, a standby or disable mode, andso forth. It should also be apparent that sensor 11 may take the formof, and be used instead of or in conjunction with other sensory devices,such as photodetectors, motion detectors, or room occupancy detectors.Conditioning circuitry 63 may perform other functions includingcombinatorial logic or other operations using a limited amount ofintelligence to provide a particular signal to input DIM of control IC61 based on signals shared with one or more sensors 11. Alternately, orin addition, control IC 61 may have multiple sensory inputs fordifferent dimming and control functions.

Control IC 61 may implement a number of control scenarios based onspecifics of lamp 12 and other components supplied with the lamp,including pre-heat time and frequency, minimum frequency, normal runningfrequency, and so forth. In addition, in accordance with the presentinvention, control IC 61 may provide functionality to compensate inputDIM in a dynamic closed loop control system when a sensor 11 isincluded. For example, a range of sensing sensitivity can be determinedby control IC 61 based on a set of characteristics provided by sensor11. One method for determining compensation when sensor 11 is aphotodetector device is to drive lamp 12 to a particular light outputlevel and to measure the signal provided by sensor 11 to obtain aparticular sensing range or normalized sense signal. In this way, theclosed loop control system can be tuned automatically, or differentsensor/lamp combinations may be used in the design without the need toprovide specific parametrics for operating the control. Alternately, orin addition, sensor 11 can be measured based on a time of day and lightoutput of lamp 12 to obtain a particular signal setting for input DIM,such as in the case of determining a sensor range or a normalized sensorsignal, for example.

The possibility exists to provide control IC 61 with further informationrelated to lighting in the room in which it is placed, such as in thecase of multiple self-dimming lamps in the same room. One or moreself-dimming lamps in accordance with the present invention may be usedto determine a light level from another lamp or self-dimming lamp, andadjust individual or a group levels accordingly.

Through sensor 11, control IC 61 may also provide a number of controloptions for implementing a particular lighting design. For example,control IC 61 may maintain a constant ambient light or constant power tolamp 12, based on the signal provided by sensor 11. In maintaining alight output level, control IC 61 may provide a measure of hysteresis toobtain an acceptable light level range that has the potential toconserve energy and/or compensate for natural light variations that mayoccur in a give environment. Control IC 61 may also have a particularlighting profile for control of lamp 12, where lamp 12 is set to amaximum output during evening hours, and a dynamic output based onsensor 11, as light levels increase near dawn, or decrease near dusk.Such a program response may be useful for security purposes, forexample, or emergency lighting or other nighttime applications. Itshould be apparent that a range of operation may be provided duringdaytime hours as light levels change in a particular environment, suchas a room with an eastward facing window that preferably has a greaterartificial illumination in the afternoon than in the morning.Alternately, control IC 61 may cause lamp 12 to follow a profile ofgreater output during daylight hours and a decreased output duringevening hours, such as may be useful in a power conservation program. Itshould be apparent that any desirable profile may be programmed intocontrol IC 61.

The dimming operation of control IC 61 is controlled through a voltagecontrolled oscillator (VCO), the parameters of which are set by externalconnections including capacitor CVCO. As the voltage applied to inputVCO of control IC 61 varies, the switching frequency of the switchinghalf bridge, including switches MHS and MLS similarly varies. Control IC61 may also incorporate some of the features provided by a dimmingballast control described in U.S. Patent Publication No. 2004/0012346,published Jan. 22, 2004, entitled “BASIC HALOGEN CONVERTER IC” by PeterGreen and lulia Rusu, the entire disclosure of which is herebyincorporated by reference.

As described above, the components within the dashed line of exampleballast 60 may be provided as design independent electronic components20, which would preferably be disposed on one surface of circuit board18 in MCM 16, for example. The components outside the dashed line may beprovided as design dependent electronic components 22 and includecomponents such as, for example, bus capacitor 26 (CBUS), filterinductor 24 (LF), or resonant inductor 28 (LRES), and certain othercomponents that can be changed to correspond to the requirements offluorescent lamp 12, e.g., resistors RFMIN or RIPH. With the particularballast circuit shown in FIG. 6, design dependent electronic components22 that are selected to meet the particular parameters of the ballastinclude resistor RIPH, which is selected to set the preheat current,capacitor CVCO, which is selected to obtain the oscillator parameters,and inductor 28 (LRES), which is selected to correspond to the lamppower. A fuse F1 may also be provided for protection.

According to a preferred method, when the dimmable electronic ballastcircuit 60 is implemented as MCM 16, for example, the passive componentsof the design independent electronic components 20 are mounted tocircuit board 18 using standard pick-and-place surface mount technology.The silicon components (e.g. ICI, MHS, MLS, the diodes) are mountedusing chip-on-board multi-chip module technology, which includesmounting the silicon components onto circuit board 18 with epoxy orsolder and then making the electrical connections with wirebonds fromthe pads located on the silicon component to the receiving pads on thecircuit board 18.

It should be noted that circuit board 18 of example MCM 16 is preferablycircular. Such shape, however, is not critical. Other shapes such as,for example, rectangular shapes can be employed without departing fromthe scope of the present invention. Furthermore, the body of circuitboard 18 may be formed from a polymer, although other suitable materialsmay be used without deviating from the present invention.

According to an aspect of the invention, MCM 16 according to thepreferred method of the present invention may be manufactured by firstinstalling design independent circuit elements 20 and covering the samewith plastic molding 51 in a first stage of production. In this stage, ageneral-purpose motherboard is formed.

Next, design dependent circuit elements 22 are installed in a secondstage of production. The second stage of production can take place at aballast manufacturer's site where design dependent circuit elements 22that are selected for each particular design can be installed. Thus, ageneral-purpose type module is manufactured in the first stage of themanufacturing of MCM 16 and then a customized or application specificballast can be manufactured in the second stage by installing designdependent circuit elements.

According to an aspect of the present invention, once design dependentcircuit elements 22 are disposed on the top side of circuit board 18,the entire structure is passed through a solder bath to electricallyconnect and mechanically secure the design dependent circuit elements 22to circuit board 18. Thus, the second stage would only require a singlestep for connecting the design dependent electronic components 22 to theother components in the ballast circuit. It is to be noted a solder bathis possible because design independent elements are covered with plasticmolding 50.

Manufacturing MCM 16 in a first stage and second stage as describedherein alleviates the need to employ a pick-and-place technique forinstalling the design dependent circuit elements 22, thus making MCM 16very attractive to production sites where hand-insertion techniques arepracticed in that no additional investment is required by themanufacturer for purchasing costly surface mount pick-and-placeequipment.

In another embodiment, only silicon components may be attached,wire-bonded (if required) and covered with plastic molding 51 in thefirst stage, and the remaining surface mounted components may beinstalled to form MCM 16 in the second stage. Such an embodimentprovides flexibility for those manufacturer's who enjoy surface mountingcapability and prefer to acquire their own surface mounted components.Very high volume productions may adopt this alternative embodiment formore economical results.

Once MCM 16 is formed, it is inserted into the interior of base 10. Base10 may be an ordinary Edison screw-base or any other conventional base,screw type or otherwise, which is used for a conventional incandescentlight bulb. Wires 42, 44 are then connected as described above, and theinterior of base 10 is then potted with thermal epoxy 40, for example,so that the heat generated by the components in MCM 16 can escapethrough base 10. MCM 16 is then connected to fluorescent lamp 12 andsensor 11, when included, either before or after insertion of MCM 16into base 10. Diffuser 14 may be attached to base 10 before orpreferably after MCM 16 is installed in base 10 with sensor 11preferably mounted on diffuser 14. Thus, diffuser 14 and fluorescentlamp 12 are attached directly to base 10 eliminating the need for anauxiliary section as required in prior art dimmable CFLPs. Nonetheless,it should again be noted that according to the present invention,diffuser 14 and fluorescent lamp 12 do not need to be directly attachedto base 10.

In an alternative embodiment a small plastic collar may be insertedbetween base 10 and diffuser 14 to ease joining, for example, glass tometal, and also when diffuser 14 has a wider mouth than the diameter ofbase 10 in order to receive fluorescent lamp 12. Alternatively, a smallcollar can be used to hold fluorescent lamp 12 and diffuser 14 and actas the interface for joining fluorescent lamp 12 and diffuser 14 to base10. The final technique used will depend on the preference at the finalmanufacturing site.

In an alternative embodiment, diffuser 14 may be omitted if the heightof fluorescent lamp 12 is low enough so that it does not protrudeoutside a fixture as prior art CFLPs. In such an embodiment, if a sensor11 is included, it may be mounted on base 10 such that the sensor clearsa socket in which CFLP 9 is inserted. Alternately sensor 11 may bemounted on lamp 12.

In an additional embodiment, diffuser 14 may be in two pieces separableat a point along its body to allow for the insertion of largerfluorescent lamps or a fluorescent lamp with a unique geometry. That is,diffuser 14 may have an open top allowing for the insertion offluorescent lamp 12 from the top.

It should be noted that example MCM 16 is not limited to the formdisclosed herein, but may be implemented using other forms. For example,MCM 16 may be implemented using two cooperatively connected circuitboards, such as, a motherboard/daughterboard arrangement. Also, MCM 16may be arranged inside base 10 in any manner, for example, verticalsideways, horizontal bottom down, and horizontal bottom up.

Referring now to FIGS. 7 and 8, in accordance with the second embodimentof the present invention, an example self-dimming lamp 70 isillustrated. Self-dimming lamp 70 is substantially similar to CFLP 9illustrated in FIG. 3, with like components indicated with likereference designators, the description of which is referred to above.

Self-dimming lamp 70 includes a photodetector 72 as sensor 11 (FIG. 3)positioned on diffuser 14 with connection wires 73 connectingphotodetector 72 to an dimmable electronic ballast 81 locatedsubstantially or entirely in base 10. Electronic ballast 81 can besimilar to that illustrated in FIG. 6, for example, but may include anytype of lamp control 85, including control IC 61, and may haveadditional inputs or facility for handling the dimming control providedby photodetector 72. Photodetector 72 is oriented to detect ambientlight in an area surrounding lamp 70, with little or no direct impactfrom the output of fluorescent lamp 12. Alternately, or in addition,photodetector 72 may detect light output directly from fluorescent lamp12, or other photodetectors may be provided to detect ambient light andindirect light from fluorescent lamp 12 as well as light directlyemitted from fluorescent lamp 12. For example, a lighting applicationmay call for a variety of types of light, where it is desirable todetect light emitted from lamp 70 as well as light from other lightsources, which may be of a different character than that emitted fromlamp 70. It may also be desirable to provide a plurality ofphotodetectors 72 to establish an ambient light operating range as wellas a range for light provided by lamp 70 that is handled by the dimmableelectronic ballast in base 10. For example, several photodetectors 72having different but overlapping ranges may be used to increase a lightsensing sensitivity of lamp 70.

Lamp control 85 includes, for example, control IC 61 illustrated in FIG.6, which may be replaced or substituted with other ballast control ICsthat have a dimming feature to which wires 73 may be connected. In sucha case, the signal carried by wires 73 from photodetector 72 providesthe dimming control signal for contributing to operating electronicballast 81 to determine programmed light levels output by lamp 70. Wires73 may be incorporated into diffuser 14, for example, and may includemultiple wires to provide a variety of functions from photodetector 72,in conjunction with other sensor devices, for example. Wires 73 may alsobe provided to obtain a sensory parametric value, such as a range oroffset for using the signal provided by photodetector 72. As discussedabove, sensor 11 may be provided as a motion detector sensor, roomoccupancy sensor, or ambient light detector, as well as a direct lightsensor that is capable of directing sensing light from fluorescent lamp12.

As shown in FIG. 8, a block diagram illustrating an example self-dimmingCFLP 80 in accordance with the second embodiment of the presentinvention is shown. Electronic ballast 81 provides the powerconditioning and lamp control for controlling lamp 12 to provide adesired light or power output. A power input stage 84 receives inputline power and conditions the input line power to provide DC power. Lampcontrol block 85 receives various inputs including power from inputstage 84 and feedback signals from photodetector 72, for example. Anumber of other parameters may be provided to lamp control 85, asdescribed above. For example, conditioning circuit 88 is optionallyprovided to condition the signal supplied by photodetector 72, or toprovide additional functionality for other sensors 11 or sensingfunctions. Circuit 88 may optionally be incorporated into eitherphotodetector 72 or lamp control 85 to permit a variety of sensors 11 tobe used with CFLP 80.

Lamp control 85 provides control signals to lamp power stage 86, whichregulates the power supplied to lamp 12 according to the controldirected by lamp control 85. In accordance with the present invention,lamp control 85 may be used with a number of lamps, where the number oflamps are driven by a single ballast with input contributed from asensor such as photodetector 72. Alternately, or in addition, one ormore lamps may be driven with input contributions from a number ofsensors that provide various input signals to lamp control 85 to obtaina particular lighting control.

Although the present invention has been described in relation toparticular embodiments thereof, many other variations and modificationsand other uses will become apparent to those skilled in the art.Therefore, the present invention should be limited not by the specificdisclosure herein, but only by the appended claims.

1. A compact fluorescent lamp package, comprising: a lamp base intendedto be inserted into an electrical socket and for electrically connectingthe lamp package to the electrical socket, the base including an openend and a closed end and a wall surrounding the closed end to provide anenclosure around a space; a complete dimmable ballast circuit containedsubstantially within the space in the base and electrically connected tothe base to receive power from the electrical socket; and a fluorescentlamp extending away from the base and operatively connected to thedimmable ballast circuit.
 2. The compact fluorescent lamp package ofclaim 1, wherein the complete dimmable ballast circuit is implemented asa multi-chip module.
 3. The compact fluorescent lamp package of claim 1,further comprising a diffuser disposed around the fluorescent lamp anddirectly connected to the lamp base.
 4. The compact fluorescent lamppackage of claim 1, wherein the lamp base is a screw-base.
 5. Thecompact fluorescent lamp package of claim 4, wherein the lamp base is anEdison screw-base.
 6. The compact fluorescent lamp package of claim 1,further comprising a thermally conductive body disposed within the lampbase and thermally connecting the lamp base to the dimmable ballastcircuit, whereby the lamp base may dissipate heat generated by thedimmable ballast circuit.
 7. A compact fluorescent lamp package of claim6, wherein said thermally conductive body is a thermal epoxy which isdisposed in the space in the base for mechanical stability and thermalmanagement.